Grasping and manipulation are fundamental ways for many creatures to interact with their environments. Different morphologies and grasping methods of “grippers” are highly evolved to adapt to harsh survival conditions. For example, human hands and bird feet are composed of rigid frames and soft joints. Compared with human hands, some plants like Drosera do not have rigid frames, so they can bend at arbitrary points of the body to capture their prey. Furthermore, many muscular hydrostat animals and plant tendrils can implement more complex twisting motions in 3D space. Recently, inspired by the flexible grasping methods present in nature, increasingly more bio‐inspired soft grippers have been fabricated with compliant and soft materials. Based on this, the present review focuses on the recent research progress of bio‐inspired soft grippers based on impactive gripping. According to their types of movement and a classification model inspired by biological “grippers”, soft grippers are classified into three types, namely, non‐continuum bending‐type grippers, continuum bending‐type grippers, and continuum twisting‐type grippers. An exhaustive and updated analysis of each type of gripper is provided. Moreover, this review offers an overview of the different stiffness‐controllable strategies developed in recent years.

The functional films based on chitosan and corn starch incorporated tea polyphenols were developed through mixing the chitosan and starch solution and the powder of tea polyphenols by the casting method. The objective of this research was to investigate the effect of different concentrations of tea polyphenols on the functional properties of the films. Attenuated total reflectance Fourier transform infrared spectrometry and X-ray diffraction were used to investigate the potential interactions among chitosan, corn starch and tea polyphenols in the blend films. Physical properties of the blend films, including density, moisture content, opacity, color, water solubility and water swelling, as well as morphological characteristics, were measured. The results demonstrated that the incorporation of tea polyphenols caused the blend films to lead to a darker appearance. The water solubility of the blend film increased with the increase of tea polyphenol concentrations, while moisture content and swelling degree decreased. The hydrogen bonding between chitosan, starch and tea polyphenols restricted the movement of molecular chains and was helpful to the stability of the blend films. The results suggested that these biodegradable blend films could potentially be used as packaging films for the food and drug industries to extend the shelf life to maintain their quality and safety.

With the emphasis placed by society on environmental resources, current petroleum-based packaging in the food industry can no longer meet people’s needs. However, new active packaging technologies have emerged, such as proteins, polysaccharides, and lipids, in which proteins are widely used for their outstanding gel film-forming properties. Most of the current literature focuses on research applications of single protein-based films. In this paper, we review the novel protein-based packaging technologies that have been used in recent years to categorize different proteins, including plant proteins (soybean protein isolate, zein, gluten protein) and animal proteins (whey protein isolate, casein, collagen, gelatin). The advances that have recently been made in protein-based active packaging technology can be understood by describing protein sources, gel properties, molding principles, and applied research. This paper presents the current problems and prospects of active packaging technology, provides new ideas for the development of new types of packaging and the expansion of gel applications in the future, and promotes the development and innovation of environmentally friendly food packaging.